Multifunctional acrylic ether-ester products modified with carboxylic anhydride or its polyacid form, process for preparing same and associated crosslinkable compositions

Multifunctional acrylated product having a number-average functionality f greater than 2.1 acrylic groups per mole of said product and with a density of said acrylic groups DA ranging from 2 to 12 mmol per g of said product, said product being the product of reaction by esterification and by etherification, by Michael addition reaction, between:

• a) a polyol R(OH)m or a mixture of polyols R(OH)m, of functionality m of at least 3 for a single polyol present and a number-average OH functionality greater than 2.1 for a mixture of said polyols, and
• b) the acrylic acid represented by R1OH,
• said reaction between a) and b) taking place in the presence of c) at least one cyclic carboxylic anhydride or of its polycarboxylic acid form R2(CO2H)z, of carboxy group (—CO2H) functionality z of at least 2 and ranging up to 4:
• the ratio r1 of number of carboxy groups of said anhydride c) relative to those of b) acrylic acid, r1=(CO2H)c/(CO2H)b ranging from 0.01 to 0.4,
• the carboxy groups being overall in stoichiometric deficit relative to the hydroxyl groups of said polyol a), with r=CO2H/OH<1,
• wherein:
• R is the residual radical of a polyol of valency m or a mixture of polyols of valency m;
• R1 is an acryloyl radical;
• and R2 is the residue of valency z of said at least one cyclic carboxylic anhydride or of its polycarboxylic acid form;
• said acrylic product comprising in its composition both:
• units A) of oligoether-ester acrylate that are derived from the reaction of a) and of b), formed by a Michael addition reaction:
• of the OH groups of said polyol a) or
• of OH groups of hydroxylated partial acrylates formed on the unsaturation of the acrylic acid b) or on the unsaturation of one of the acrylates formed by esterification with b) and simultaneous esterification with b) of said polyol a) and of said b hydroxylated partial acrylates or simultaneous esterification with the carboxy groups of the carboxylated Michael adduct formed between a) and b), and
• units B) of oligoester acrylates derived from c) by a reaction of esterification with said anhydride or with its polyacid form c) of said polyol a) or of said hydroxylated partial acrylates or of the hydroxylated ether-ester acrylates formed,
• said acrylic product being a mixture of acrylic products comprising at least one acrylic product (p1) chemically linking, in its molecular structure, the units A) and B) as defined above, wherein the product has an overall composition represented by the following average general formula (I):
• R1O-[[A]a-[B]b]n—R(OR1)m-1 (I)
• with a and b representing the average mole fraction of each unit A) and B) per overall average unit of said product and with a+b=1 and a/b ranging from 0.15 to 22, n being the number of repeat overall units, with average n per mole of product nave ranging from 0.2 to 10.